The present invention relates as indicated to a fill slat assembly for cooling towers, and relates more particularly to a perforated fill slat assembly for use with crossflow air systems.
The use of fill slats, also commonly referred to as splash bars, in cooling towers is well known in the art. The fill slats are normally positioned in the tower in vertically and laterally spaced position to provide a tortuous passage for the water descending in the cooling tower. In this manner, the water is diverted upon contact with a particular fill slat and directed laterally to contact a laterally adjacent fill slat at a lower level in the cooling tower. Where fill slats are formed with perforations, water passing directly through the perforations will descend for contact with the fill slat positions directly below. In this manner, the water to be cooled, which is admitted at the top of the cooling tower, is broken up into droplets as it descends through the tower, thereby inhancing vaporization and thus cooling the water. Where water temporarily remains on the surface of the fill slat, it is in the nature of a very thin film, which likewise enhances vaporization. The cooling process is further enhanced by the flowing of air laterally through a side or sides of the tower in a direction generally either parallel or transverse to the fill slats, and then upwardly through the tower for exhausting the air from the top of the tower. The cooled water is collected at the bottom of the tower and routed for reuse for further cooling.
The prior art is replete with the fill slats or splash bars of the general type referred to above, and the use of fill slats having perforations is also well known in the art. Reference is made, for example, to U.S. Pat. Nos. 3,083,148 to Mojonnier; 3,389,895 to DeFlon; 3,647,191 to Fordyce; 3,743,257 to Fordyce; 4,020,130 to Ovard, and 4,133,851 to Ovard, all of which disclose performated fill members of varying configuration and function. Although the last mentioned Ovard patent is relevant to the present invention in certain respects, there are several disadvantages in connection with the handling and installation of the fill slat shown in Ovard. Although certain forms of fill slats shown in Ovard are provided with slotted bevelled edges, with the slots receiving the horizontal and vertical support wires or rods, rolling or tilting movement of the fill slats is not precluded, nor is longitudinal movement of the fill slat totally prevented. This latter feature is particularly important in view of the frictional contact between the wires and the slots and the consequent wear on the fill slats. Moreover, the construction of all of the several forms of Ovard are such that shipping costs are relatively high. The fill slats cannot be nested during shipment, and as a result the volume required for shipping a corresponding number of fill slats is substantially larger.